Inhalation exposure to semi-volatile PCBs in industrial cities, near the Great Lakes, in areas where dredging is occurring and at remediation sites has the potential to cause neurological, reproductive, and immunological toxicity in humans and animals. The Inhalation Toxicology Core was established with the primary goal to serve the projects and other research support cores with state-of-the-art animal facilities and rigorously controlled inhalation exposures to realistic mixtures of airborne PCB congeners. The specific aims of this Core are: Aim 1) Generate controlled PCB atmospheres in exposure chambers and collect airborne PCBs resulting from vaporization of common industrial PCB mixtures (supports Projects 1, 2, 3, 5 and the Analytical and Synthesis Cores); Aim 2) Perform acute, subacute and subchronic inhalation exposures of laboratory animals to defined mixtures of atmospheric PCBs and to individual congeners, (supports Projects 1 and 2); Aim 3) Provide a rodent vivarium for experimental animals used for the isbrp and execute a quality assurance program to monitor their health and welfare (supports Projects 1, 2, and 3); Aim 4) Perform necropies on exposed, control and sentinel rodents and distribute tissues to project investigators in the isbrp (supports Projects 1,2, and 3). The Inhalation Toxicology Core exists within the Pulmonary Toxicology Facility (PTF) of the Environmental Health Sciences Research Center and consists of 6,000 ft2 of contiguous laboratories and offices. The PTF is nationally recognized for innovative animal models and exposure delivery systems. A full array of inhalation toxicology, aerosol science, and bioassay services are rendered. The Inhalation Toxicology Core is well equipped for generating and quantifying PCB vapors or aerosols; for performing nose-only inhalation exposures of rats and mice in acute, subacute or subchronic protocols; and for determining the degree of exposure and response. A new aim in this renewal is: Aim 5) Perform airborne exposures to primary alveolar and airway epithelia and epithelial cell lines in Transwells with an apical air interface using vapor phase and particle bound PCB congeners. This will bring to the program a new approach for studying toxic effects of airborne PCBs on epithelial cells.